feat(rust-proxy-engine): add a Rust SIP proxy engine with shared SIP and codec libraries

rust/crates/proxy-engine/src/call.rs

@@ -0,0 +1,103 @@
+//! Call hub — owns legs and bridges media.
+//!
+//! Each Call has a unique ID and tracks its state, direction, and associated
+//! SIP Call-IDs for message routing.
+
+use std::net::SocketAddr;
+use std::sync::Arc;
+use std::time::Instant;
+use tokio::net::UdpSocket;
+
+/// Call state machine.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CallState {
+    SettingUp,
+    Ringing,
+    Connected,
+    Voicemail,
+    Ivr,
+    Terminating,
+    Terminated,
+}
+
+impl CallState {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::SettingUp => "setting-up",
+            Self::Ringing => "ringing",
+            Self::Connected => "connected",
+            Self::Voicemail => "voicemail",
+            Self::Ivr => "ivr",
+            Self::Terminating => "terminating",
+            Self::Terminated => "terminated",
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CallDirection {
+    Inbound,
+    Outbound,
+}
+
+impl CallDirection {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::Inbound => "inbound",
+            Self::Outbound => "outbound",
+        }
+    }
+}
+
+/// A passthrough call — both sides share the same SIP Call-ID.
+/// The proxy rewrites SDP/Contact/Request-URI and relays RTP.
+pub struct PassthroughCall {
+    pub id: String,
+    pub sip_call_id: String,
+    pub state: CallState,
+    pub direction: CallDirection,
+    pub created_at: Instant,
+
+    // Call metadata.
+    pub caller_number: Option<String>,
+    pub callee_number: Option<String>,
+    pub provider_id: String,
+
+    // Provider side.
+    pub provider_addr: SocketAddr,
+    pub provider_media: Option<SocketAddr>,
+
+    // Device side.
+    pub device_addr: SocketAddr,
+    pub device_media: Option<SocketAddr>,
+
+    // RTP relay.
+    pub rtp_port: u16,
+    pub rtp_socket: Arc<UdpSocket>,
+
+    // Packet counters.
+    pub pkt_from_device: u64,
+    pub pkt_from_provider: u64,
+}
+
+impl PassthroughCall {
+    pub fn duration_secs(&self) -> u64 {
+        self.created_at.elapsed().as_secs()
+    }
+
+    pub fn to_status_json(&self) -> serde_json::Value {
+        serde_json::json!({
+            "id": self.id,
+            "state": self.state.as_str(),
+            "direction": self.direction.as_str(),
+            "callerNumber": self.caller_number,
+            "calleeNumber": self.callee_number,
+            "providerUsed": self.provider_id,
+            "createdAt": self.created_at.elapsed().as_millis(),
+            "duration": self.duration_secs(),
+            "rtpPort": self.rtp_port,
+            "pktFromDevice": self.pkt_from_device,
+            "pktFromProvider": self.pkt_from_provider,
+        })
+    }
+}